Expedited transfer to a cardiac arrest centre for non-ST-elevation out-of-hospital cardiac arrest (ARREST): a UK prospective, multicentre, parallel, randomised clinical trial.

BACKGROUND: The International Liaison Committee on Resuscitation has called for a randomised trial of delivery to a cardiac arrest centre. We aimed to assess whether expedited delivery to a cardiac arrest centre compared with current standard of care following resuscitated cardiac arrest reduces deaths. METHODS: ARREST is a prospective, parallel, multicentre, open-label, randomised superiority trial. Patients (aged ≥18 years) with return of spontaneous circulation following out-of-hospital cardiac arrest without ST elevation were randomly assigned (1:1) at the scene of their cardiac arrest by London Ambulance Service staff using a secure online randomisation system to expedited delivery to the cardiac catheter laboratory at one of seven cardiac arrest centres or standard of care with delivery to the geographically closest emergency department at one of 32 hospitals in London, UK. Masking of the ambulance staff who delivered the interventions and those reporting treatment outcomes in hospital was not possible. The primary outcome was all-cause mortality at 30 days, analysed in the intention-to-treat (ITT) population excluding those with unknown mortality status. Safety outcomes were analysed in the ITT population. The trial was prospectively registered with the International Standard Randomised Controlled Trials Registry, 96585404. FINDINGS: Between Jan 15, 2018, and Dec 1, 2022, 862 patients were enrolled, of whom 431 (50%) were randomly assigned to a cardiac arrest centre and 431 (50%) to standard care. 20 participants withdrew from the cardiac arrest centre group and 19 from the standard care group, due to lack of consent or unknown mortality status, leaving 411 participants in the cardiac arrest centre group and 412 in the standard care group for the primary analysis. Of 822 participants for whom data were available, 560 (68%) were male and 262 (32%) were female. The primary endpoint of 30-day mortality occurred in 258 (63%) of 411 participants in the cardiac arrest centre group and in 258 (63%) of 412 in the standard care group (unadjusted risk ratio for survival 1·00, 95% CI 0·90-1·11; p=0·96). Eight (2%) of 414 patients in the cardiac arrest centre group and three (1%) of 413 in the standard care group had serious adverse events, none of which were deemed related to the trial intervention. INTERPRETATION: In adult patients without ST elevation, transfer to a cardiac arrest centre following resuscitated cardiac arrest in the community did not reduce deaths. FUNDING: British Heart Foundation.

The influence of biological age and sex on long-term outcome after percutaneous coronary intervention for ST-elevation myocardial infarction.

BACKGROUND: Outcome following ST-segment elevation myocardial infarction (STEMI) is thought to be worse in women than in age-matched men. We assessed whether such differences occur in the UK Pan-London dataset and if age, and particularly menopause, influences upon outcome. METHODS: We undertook an observational cohort study of 26,799 STEMI patients (20,633 men, 6,166 women) between 2005-2015 at 8 centres across London, UK. Patient details were recorded at the time of the procedure into local databases using the British Cardiac Intervention Society (BCIS) PCI dataset. Primary outcome was all-cause mortality at a median follow-up of 4.1 years (IQR: 2.2-5.8 years). RESULTS: Kaplan-Meier analysis demonstrated a higher mortality rate in women versus men (15.6% men vs. 25.3% women, P<0.0001). Univariate Cox analysis revealed that female sex was a predictor of all-cause mortality (HR: 1.69 95% CI: 1.59-1.82). However, after multivariate adjustment, this effect of female sex diminished (HR: 1.05 95% CI: 0.90-1.25). In a sub-group analysis, we compared the sexes separated by age into the ≤55 and the >55 year olds. Age-stratified Cox analysis revealed that female sex was a univariate predictor of all-cause mortality (HR: 1.60 95% CI: 1.25-2.05) in the ≤55 group and in the >55 group (HR: 1.38 95% CI: 1.28-1.47). However, after regression adjustment incorporating the propensity score into a proportional hazard model as a covariate, whilst female sex was not a significant predictor of all-cause mortality in the ≤55 group it was a predictor in the >55 group. Moreover, whilst age did not influence outcome in <55 group, this effect in the >55 group was correlated with age. CONCLUSIONS: Overall women have a worse all-cause mortality following primary PCI for STEMI compared to men. However, this effect was driven predominantly by women >55 years of age since after adjusting for co-morbidities the risk in younger women did not differ significantly from that in men. These observations support the view that as women advance past the menopausal years their risk of further events following revascularization increases substantially and we suggest that routine assessment of hormonal status may improve clinical decision-making and ultimately outcome for women post-PCI.

Impact of Early (≤24 h) Versus Delayed (>24 h) Intervention in Patients With Non-ST Segment Elevation Myocardial Infarction: An Observational Study of 20,882 Patients From the London Heart Attack Group.

INTRODUCTION: We aimed to investigate the optimal timing of invasive coronary angiography and subsequent intervention in non-ST-segment elevation acute myocardial infarction (NSTEMI) patients. METHODS: We examined the impact of early (≤24 h) versus delayed (>24 h) intervention in a large observational cohort of 20,882 consecutive NSTEMI patients treated with PCI between 2005 and 2015 at 8 tertiary cardiac centers in London (UK) using Cox-regression analysis and propensity matching. RESULTS: Mean age was 64.5 ± 12.7 years and 26.1% were females. A quarter (27.6%), were treated within 24 h. Patients treated within 24 h were slightly younger (62.8 ± 12.8 vs. 65.2 ± 12.6, p < 0.001), most commonly male (76% vs. 72.9%, p < 0.001) and were more frequently ventilated (2.3% vs. 1.4%, p < 0.001) and in cardiogenic shock (3.6% vs. 1.4%, p < 0.001) with dynamic changes on their ECG (84.5% vs. 76.1% p < 0.001). At a median follow up of 4.2 years (interquartile range 1.8 to 7) 17.7% of patients had died. Estimated 5-year survival in patients treated within 24 h was 84.6% vs. 81% for those treated >24 h following their presentation (p < 0.001). This survival benefit remained following adjustment for confounders; HR(delayed vs. early management) 1.11 (95%CI 1.003 to 1.23, p = 0.046). In the propensity matched cohort of 4356 patients in each group, there remained a trend for higher survival in the early intervention group (p = 0.061). CONCLUSIONS: Notwithstanding the limitations of the retrospective design, this real-world cohort of NSTEMI patients suggests that an early intervention (≤24 h) may improve mid-term survival.

COVID-19 pandemic and STEMI: pathway activation and outcomes from the pan-London heart attack group.

OBJECTIVES: To understand the impact of COVID-19 on delivery and outcomes of primary percutaneous coronary intervention (PPCI). Furthermore, to compare clinical presentation and outcomes of patients with ST-segment elevation myocardial infarction (STEMI) with active COVID-19 against those without COVID-19. METHODS: We systematically analysed 348 STEMI cases presenting to the PPCI programme in London during the peak of the pandemic (1 March to 30 April 2020) and compared with 440 cases from the same period in 2019. Outcomes of interest included ambulance response times, timeliness of revascularisation, angiographic and procedural characteristics, and in-hospital clinical outcomes RESULTS: There was a 21% reduction in STEMI admissions and longer ambulance response times (87 (62-118) min in 2020 vs 75 (57-95) min in 2019, p<0.001), but that this was not associated with a delays in achieving revascularisation once in hospital (48 (34-65) min in 2020 vs 48 (35-70) min in 2019, p=0.35) or increased mortality (10.9% (38) in 2020 vs 8.6% (38) in 2019, p=0.28). 46 patients with active COVID-19 were more thrombotic and more likely to have intensive care unit admissions (32.6% (15) vs 9.3% (28), OR 5.74 (95%CI 2.24 to 9.89), p<0.001). They also had increased length of stay (4 (3-9) days vs 3 (2-4) days, p<0.001) and a higher mortality (21.7% (10) vs 9.3% (28), OR 2.72 (95% CI 1.25 to 5.82), p=0.012) compared with patients having PPCI without COVID-19. CONCLUSION: These findings suggest that PPCI pathways can be maintained during unprecedented healthcare emergencies but confirms the high mortality of STEMI in the context of concomitant COVID-19 infection characterised by a heightened state of thrombogenicity.

Prior Coronary Artery Bypass Graft Surgery and Outcome After Percutaneous Coronary Intervention: An Observational Study From the Pan-London Percutaneous Coronary Intervention Registry.

Background Limited information exists regarding procedural success and clinical outcomes in patients with previous coronary artery bypass grafting (CABG) undergoing percutaneous coronary intervention (PCI). We sought to compare outcomes in patients undergoing PCI with or without CABG. Methods and Results This was an observational cohort study of 123 780 consecutive PCI procedures from the Pan-London (UK) PCI registry from 2005 to 2015. The primary end point was all-cause mortality at a median follow-up of 3.0 years (interquartile range, 1.2-4.6 years). A total of 12 641(10.2%) patients had a history of previous CABG, of whom 29.3% (n=3703) underwent PCI to native vessels and 70.7% (n=8938) to bypass grafts. There were significant differences in the demographic, clinical, and procedural characteristics of these groups. The risk of mortality during follow-up was significantly higher in patients with prior CABG (23.2%; P=0.0005) compared with patients with no prior CABG (12.1%) and was seen for patients who underwent either native vessel (20.1%) or bypass graft PCI (24.2%; P<0.0001). However, after adjustment for baseline characteristics, there was no significant difference in outcomes seen between the groups when PCI was performed in native vessels in patients with previous CABG (hazard ratio [HR],1.02; 95%CI, 0.77-1.34; P=0.89), but a significantly higher mortality was seen among patients with PCI to bypass grafts (HR,1.33; 95% CI, 1.03-1.71; P=0.026). This was seen after multivariate adjustment and propensity matching. Conclusions Patients with prior CABG were older with greater comorbidities and more complex procedural characteristics, but after adjustment for these differences, the clinical outcomes were similar to the patients undergoing PCI without prior CABG. In these patients, native-vessel PCI was associated with better outcomes compared with the treatment of vein grafts.

Outcome of inter-hospital transfer versus direct admission for primary percutaneous coronary intervention: An observational study of 25,315 patients with ST-elevation myocardial infarction from the London Heart Attack Group.

BACKGROUND AND AIMS: In patients with ST-segment elevation myocardial infarction (STEMI), mortality is directly related to time to reperfusion with guidelines recommending patients be delivered directly to centres for primary percutaneous coronary intervention (PCI). The aim of this study was to describe the impact of inter-hospital transfer on reperfusion time and to assess whether or not treatment delays influenced clinical outcomes in comparison with direct admission to a primary PCI centre in a large regional network. METHOD AND RESULTS: We undertook an observational cohort study of patients with STEMI treated with primary PCI between 2005 and 2015 in London, UK. Patient details were recorded at the time of the procedure in databases using the British Cardiovascular Intervention Society PCI dataset. The primary end-point was all-cause mortality at a median of 4.1 years (interquartile range: 2.2-5.8 years). Secondary outcomes were in-hospital major adverse cardiac events. Of 25,315 patients, 17,560 (69.4%) were admitted directly to a primary PCI centre and 7755 (31.6%) were transferred from a non-primary PCI centre. Patients in the direct admission group were older and more likely to have left ventricular impairment compared with the inter-hospital transfer group. Median time from call for help to reperfusion in transferred patients was 52 minutes longer compared with patients admitted directly (p <0.001). However, call to first hospital admission was similar. Kaplan-Meier analysis demonstrated significantly lower mortality rates in patients who were transferred directed to a primary PCI centre compared with patients who were transferred from a non-PCI centre (17.4% direct vs. 18.7% transfer, p=0.017). Furthermore, after propensity matching, direct admission for primary PCI was still a predictor of all-cause mortality (hazard ratio: 0.89, 95% confidence interval: 0.64-0.95). CONCLUSIONS: In this large registry of over 25,000 STEMI patients treated by primary PCI survival was better in patients admitted directly to a cardiac centre versus patients transferred for primary PCI, most likely due to longer call to balloon times in patient transferred from other hospitals.

Complete Versus Culprit only Revascularisation in Patients with Cardiogenic Shock Complicating Acute Myocardial Infarction: Incidence and Outcomes from the London Heart Attack Group.

BACKGROUND: Despite advances in technology, patients with Cardiogenic Shock (CS) presenting with ST-segment myocardial infarction (STEMI) still have a poor prognosis with high mortality rates. A large proportion of these patients have multi-vessel coronary artery disease, the treatment of which is still unclear. We aimed to assess the trends in management of CS patients with multi-vessel disease (MVD), particularly looking at the incidence and outcomes of complete revascularisation compared to culprit vessel only. METHODS AND RESULTS: We undertook an observational cohort study of 21,210 STEMI patients treated between 2005 and 2015 at the 8 Heart Attack Centres in London, UK. Patients' details were recorded prospectively into local databases using the British Cardiac Intervention Society (BCIS) PCI dataset. 1058 patients presented with CS and MVD. Primary outcome was all-cause mortality. Patients were followed-up for a median of 4.1 years (IQR range: 2.2-5.8 years). 497 (47.0%) patients underwent complete revascularisation during primary PCI for CS with stable rates seen over time. These patients were more likely to be male, hypertensive and more likely to have poor LV function compared to the culprit vessel intervention group. Although crude, in hospital major adverse cardiac events (MACE) rates were similar (40.8% vs. 36.0%, p = 0.558) between the two groups. Kaplan-Meier analysis demonstrated no significant differences in mortality rates between the two groups (53.8% complete revascularisation vs. 46.8% culprit vessel intervention, p = 0.252) during the follow-up period. After multivariate cox analysis (HR 0.69 95% CI (0.44-0.98)) and the use of propensity matching (HR: 0.81 95% CI: 0.62-0.97) complete revascularisation was associated with reduced mortality. A number of co-variates were included in the model, including age, gender, diabetes, hypertension, hypercholesterolaemia, previous PCI, previous MI, chronic renal failure, Anterior infarct, number of treated vessels, pre-procedure TIMI flow, procedural success and GP IIb/IIIA use. CONCLUSION: In a contemporary observational series of CS patients with MVD, complete revascularisation appears to be associated with better outcomes compared to culprit vessel only intervention. This supports on-going clinical trials in this area and provides further evidence of the association of complete revascularisation in STEMI with good outcomes.

The association between the public reporting of individual operator outcomes with patient profiles, procedural management, and mortality after percutaneous coronary intervention: an observational study from the Pan-London PCI (BCIS) Registry using an interrupted time series analysis.

AIMS: The public reporting of healthcare outcomes has a number of potential benefits; however, unintended consequences may limit its effectiveness as a quality improvement process. We aimed to assess whether the introduction of individual operator specific outcome reporting after percutaneous coronary intervention (PCI) in the UK was associated with a change in patient risk factor profiles, procedural management, or 30-day mortality outcomes in a large cohort of consecutive patients. METHODS AND RESULTS: This was an observational cohort study of 123 780 consecutive PCI procedures from the Pan-London (UK) PCI registry, from January 2005 to December 2015. Outcomes were compared pre- (2005-11) and post- (2011-15) public reporting including the use of an interrupted time series analysis. Patients treated after public reporting was introduced were older and had more complex medical problems. Despite this, reported in-hospital major adverse cardiovascular and cerebrovascular events rates were significantly lower after the introduction of public reporting (2.3 vs. 2.7%, P < 0.0001). Interrupted time series analysis demonstrated evidence of a reduction in 30-day mortality rates after the introduction of public reporting, which was over and above the existing trend in mortality before the introduction of public outcome reporting (35% decrease relative risk 0.64, 95% confidence interval 0.55-0.77; P < 0.0001). CONCLUSION: The introduction of public reporting has been associated with an improvement in outcomes after PCI in this data set, without evidence of risk-averse behaviour. However, the lower reported complication rates might suggest a change in operator behaviour and decision-making confirming the need for continued surveillance of the impact of public reporting on outcomes and operator behaviour.

Assessing cardiovascular risk in chronic kidney disease patients prior to kidney transplantation: clinical usefulness of a standardised cardiovascular assessment protocol.

BACKGROUND: Despite pre-kidney-transplant cardiovascular (CV) assessment being routine care to minimise perioperative risk, the utility of such assessment is not well established. The study reviewed the evaluation and outcome of a standardised CV assessment protocol. METHODS: Data were analysed for 231 patients (age 53.4 ± 12.9 years, diabetes 34.6%) referred for kidney transplantation between 1/2/2012-31/12/2014. One hundred forty-three patients were high-risk (age > 60 years, diabetes, CV disease, heart failure, peripheral vascular disease) and offered dobutamine stress echocardiography (DSE); 88 patients were low-risk and offered ECG and echocardiography with/without exercise treadmill test. RESULTS: At the end of follow-up (579 ± 289 days), 35 patients underwent kidney transplantation and 50 were active on the waitlist. There were 24 events (CV or death), none were perioperative. One hundred fifteen patients had DSE with proportionally more events in DSE-positive compared to DSE-negative patients (6/34 vs. 7/81, p = 0.164). In 42 patients who underwent coronary angiography due to a positive DSE or ischaemic heart disease symptoms, 13 (31%) had events, 6 were suspended, 11 removed from waitlist, 3 wait-listed, 1 transplanted and 17 still undergoing assessment. Patients with significant coronary artery disease requiring intervention had poorer event-free survival compared to those without intervention (56% vs. 83% at 2 years, p = 0.044). However, the association became non-significant after correction for CV risk factors (HR = 3.17, 95% CI 0.51-19.59, p = 0.215). CONCLUSIONS: The stratified CV risk assessment protocol using DSE in all high-risk patients was effective in identifying patients with coronary artery disease. The coronary angiograms identified the event-prone patients effectively but coronary interventions were not associated with improved survival.

Time-trend analyses of bleeding and mortality after primary percutaneous coronary intervention during out of working hours versus in-working hours: an observational study of 11 466 patients.

BACKGROUND: Primary percutaneous coronary intervention (PPCI) is the treatment of choice for ST-segment-elevation myocardial infarction. Resources are limited during out of working hours (OWH). Whether PPCI outside working hours is associated with worse outcomes and whether outcomes have improved over time are unknown. METHODS AND RESULTS: We analyzed 11 466 patients undergoing PPCI between 2004 and 2011 at all 8 tertiary cardiac centers in London, United Kingdom. We defined working hours as 9 am to 5 pm (Monday to Friday). We analyzed in-hospital bleeding and all-cause mortality ≤3 years, comparing OWH versus in-working hours. A total of 7494 patients (65.3%) were treated during OWH. Multivariable analyses demonstrated that PPCI during OWH was not a predictor for bleeding (odds ratio, 1.47; 95% confidence interval [CI], 0.97-2.24; P=0.071) or 3-year mortality (hazard ratio, 1.11; 95% CI, 0.94-1.32; P=0.20). This was confirmed in propensity-matched analyses. Time-stratified analyses demonstrated that PPCI during OWH was a predictor for bleeding (odds ratio, 2.00; 95% CI, 1.06-3.80; P=0.034) and 3-year mortality during 2005 to 2008 (hazard ratio, 1.23; 95% CI, 1.00-1.50; P=0.050), but this association was lost during 2009 to 2011. During 2005 to 2008, transradial access was predominantly used during in-working hours and PPCI during OWH was predictive of reduced transradial access use (odds ratio, 0.83; 95% CI, 0.71-0.98; P=0.033), but this association was lost during 2009 to 2011. CONCLUSIONS: In this study of unselected patients with ST-segment-elevation myocardial infarction, PPCI during OWH versus in-working hours had comparable bleeding and mortality. Time-stratified analyses demonstrated a reduction in adjusted bleeding and mortality during OWH over time. This may reflect the improved service provision, but the increased adoption of transradial access during OWH may also be contributory.

Culprit vessel versus multivessel intervention at the time of primary percutaneous coronary intervention in patients with ST-segment-elevation myocardial infarction and multivessel disease: real-world analysis of 3984 patients in London.

BACKGROUND: It is estimated that up to two thirds of patients presenting with ST-segment-elevation myocardial infarction have multivessel disease. The optimal strategy for treating nonculprit disease is currently under debate. This study provides a real-world analysis comparing a strategy of culprit-vessel intervention (CVI) versus multivessel intervention at the time of primary percutaneous coronary intervention in patients with ST-segment-elevation myocardial infarction. METHODS AND RESULTS: We compared CVI versus multivessel intervention in 3984 patients with multivessel disease undergoing primary percutaneous coronary intervention between 2004 and 2011 at all 8 tertiary cardiac centers in London. Multivariable-adjusted models were built to determine independent predictors for in-hospital major adverse cardiovascular events (MACEs) and all-cause mortality at 1 year. To reduce confounding and bias, propensity score methods were used. CVI was associated with reduced in-hospital MACE (4.6% versus 7.2%; P=0.010) and mortality at 1 year (7.4% versus 10.1%; P=0.031). CVI was an independent predictor for reduced in-hospital MACE (odds ratio, 0.49; 95% confidence interval [CI], 0.32-0.75; P<0.001) and survival at 1 year (hazard ratio, 0.65; 95% CI, 0.47-0.91; P=0.011) in the complete cohort; and in 2821 patients in propensity-matched cohort (in-hospital MACE: odds ratio, 0.49; 95% CI, 0.32-0.76; P=0.002; and 1-year survival: hazard ratio, 0.64; 95% CI, 0.45-0.90; P=0.010). Inverse probability treatment weighted analyses also confirmed CVI as an independent predictor for reduced in-hospital MACE (odds ratio, 0.38; 95% CI, 0.15-0.96; P=0.040) and survival at 1 year (hazard ratio, 0.44; 95% CI, 0.21-0.93; P=0.033). CONCLUSIONS: In this observational analysis of patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention, CVI was associated with increased survival at 1 year. Acknowledging the limitations with observational analyses, our findings support current recommended practice guidelines.

Radial versus femoral access is associated with reduced complications and mortality in patients with non-ST-segment-elevation myocardial infarction: an observational cohort study of 10,095 patients.

BACKGROUND: Compared with transfemoral access, transradial access (TRA) for percutaneous coronary intervention is associated with reduced risk of bleeding and vascular complications. Studies suggest that TRA may reduce mortality in patients with ST-segment-elevation myocardial infarction. However, there are few data on the effect of TRA on mortality, specifically, in patients with non-ST-segment-elevation myocardial infarction. METHODS AND RESULTS: We analyzed 10 095 consecutive patients with non-ST-segment-elevation myocardial infarction treated with percutaneous coronary intervention between 2005 and 2011 in all 8 tertiary cardiac centers in London, United Kingdom. TRA was a predictor for reduced bleeding (odds ratio=0.21; 95% confidence interval [CI]: 0.08-0.57; P=0.002), access-site complications (odds ratio=0.47; 95% CI: 0.23-0.95; P=0.034), and 1-year mortality (hazard ratio [HR]=0.72; 95% CI: 0.54-0.94; P=0.017). Between 2005 and 2007, TRA did not appear to reduce mortality at 1 year (HR=0.81; 95% CI: 0.51-1.28; P=0.376), whereas between 2008 and 2011, TRA conferred survival benefit at 1 year (HR=0.65; 95% CI: 0.46-0.92; P=0.015). The mortality benefit with TRA at 1 year was not seen at the low-volume centers (HR=0.80; 95% CI: 0.47-1.38; P=0.428) but specifically seen in the high volume radial centers (HR=0.70; 95% CI: 0.51-0.97; P=0.031). In propensity-matched analyses, TRA remained a predictor for survival at 1 year (HR=0.60; 95% CI: 0.42-0.85; P=0.005). Instrumental variable analysis demonstrated that TRA conferred mortality benefit at 1-year with an absolute mortality reduction of 5.8% (P=0.039). CONCLUSIONS: In this analysis of patients with non-ST-segment-elevation myocardial infarction, TRA appears to be a predictor for survival. Furthermore, the evolving learning curve, experience, and expertise may be important factors contributing to the prognostic benefit conferred with TRA.

Atriobiventricular pacing improves exercise capacity in patients with heart failure and intraventricular conduction delay.

OBJECTIVES: We sought to assess the efficacy of biventricular pacing with respect to both peak and submaximal measures of exercise in patients with New York Heart Association class III heart failure (HF) and intraventricular conduction delay in a randomized, blinded study. BACKGROUND: Submaximal and maximal changes in exercise capacity need evaluating in this patient population with this novel therapy. METHODS: Graded exercise and 6-min walk tests were performed in patients randomized to three months each of active (atrio-biventricular) and inactive pacing. Minute ventilation (VE), oxygen uptake (VO(2)), ventilated carbon dioxide (VCO(2)) and heart rate were measured in patients achieving a respiratory quotient >1 (n = 30). Oxygen pulse, anaerobic threshold (AT) and ventilatory efficiency (VE/VCO(2)) were calculated. RESULTS: Active biventricular pacing increased peak VO(2) (15.8 +/- 4.3 vs. 14.4 +/- 4.6 ml/kg/min, p = 0.02), exercise time (501 +/- 223 s vs. 437 +/- 233 s, p < 0.001) and oxygen pulse (9.3 +/- 2.8 vs. 8.1 +/- 3.1 ml/beat, p < 0.01) compared with inactive pacing. The submaximal measures of exercise capacity significantly increased with active pacing: AT (11.2 +/- 4.1 ml/kg/min vs. 9.5 +/- 2.3 ml/kg/min, p = 0.02) and 6-min walk (414 +/- 94 m vs. 359 +/- 94 m, p = 0.001). Minute ventilation/ventilated carbon dioxide improved (32 +/- 9 vs. 36 +/- 11, p = 0.03) with normalization of the VE/VCO(2) slope in 59% of patients (chi-square test, p = 0.002) with active pacing. CONCLUSIONS: Biventricular pacing may improve maximal and submaximal exercise capacity in patients with advanced HF and intraventricular conduction delay.

Sudden death in young athletes: HCM or ARVC?

Sudden non-traumatic death in young athletes is due to underlying congenital/inherited cardiac diseases in over 80% of cases. The two commonest conditions leading to sudden cardiac death in athletes below the age of 25 years are hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Hypertrophic cardiomyopathy is caused by mutations in genes, which code for sarcomeric contractile proteins. It can present with symptoms such as palpitation, presyncope or syncope. In a small number of cases, sudden death is the first clinical manifestation of the condition. It is well established that HCM accounts for over half of all cases sudden cardiac death in young individuals below 25 years of age. The management of HCM broadly encompasses symptom control, familial evaluation and the prevention of sudden death. Arrhythmogenic right ventricular cardiomyopathy, similarly, is a genetic disorder of the heart muscle and leads to symptoms such as palpitation and syncope and more rarely sudden death. The diagnosis of ARVC is most likely underestimated due to the lack of a single diagnostic test and subtle morphological changes in some cases. The diagnosis is based on clinical and family history and non-invasive investigations. The physiological adaptations seen in some athletes, as a response to physical training, may resemble phenotypically mild forms HCM and ARVC. Therefore, a diagnostic algorithm enabling this differentiation would be of importance especially bearing in mind the consequences of a misdiagnosis.